A group of aerobic microorganisms known as methanotrophs have previously been used to degrade organic contaminants. This group of organisms produces monooxygenases which oxidize methane and, in the absence of methane, after the enzyme has been produced, will incidently oxidize other compounds such as halogenated hydrocarbons, alkanes, alcohols, etc.
One of the more prevalent contaminants which have been degraded by co-metabolisms using methanotrophs is trichloroethylene. (TCE), an organic solvent that is used widely for metal processing, dry cleaning and in production of coatings. Because of leaks, spills and dumping, TCE is frequently found in subsurface soil environments. TCE is one of the most commonly found pollutants at hazardous waste sites. TCE and other chlorinated hydrocarbons are frequent pollutants of ground water. Most attempts to remediate the contamination of soils and aquifers have involved use of pump or vacuum means to bring the contaminated material to the surface for treatment. These means have resulted in limited removal of contaminants. The prior art practices are expensive and generally have no end-point to their operations. Limitations relating to hydraulic conductivity, soil matrix, desorption and residual saturation or pockets of contaminants present real problems when practicing the prior art methods of remediation.
An electrokinetic process developed by Casagrande has been used to dewater soils. This process has been used to remove contaminants from soil and aquifers. The process utilizes a direct current (DC electric field to induce the movement of water and dissolved ions as a means of transporting the contaminant. The method is beneficial only when contaminants are reasonably soluble in water (for example, benzene, toluene, xylene, phenol and chlorinated solvents). Moreover, the electrokinetic process results in transport, not degradation, of the contaminants. Therefore, electrokinetic application to soil provides only an incomplete solution to problems of contamination of soil and water. Ho has applied the electrokinetic methods to movement and capture of p-nitrophenol (PNP) with granular activated carbon (GAC) filled cassettes. However, the problems relating to removing and disposing of the contaminated cassettes remain unsolved.